# -*- coding: utf-8 -*-
"""
Created on Tue Oct 24 19:51:07 2023

@author: 楠川之木
"""

import re

def extract_three_letter_words(text):
    pattern = r'\b[a-zA-Z]{3}\b'
    result = re.findall(pattern, text)
    return result

# 从键盘输入英文文本
text = input("请输入一段英文文本：")

# 提取长度为 3 个字母的单词
three_letter_words = extract_three_letter_words(text)

# 输出结果
print("长度为 3 个字母的单词：", three_letter_words)